[Federal Register Volume 87, Number 142 (Tuesday, July 26, 2022)]
[Proposed Rules]
[Pages 44281-44283]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2022-15854]
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Proposed Rules
Federal Register
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This section of the FEDERAL REGISTER contains notices to the public of
the proposed issuance of rules and regulations. The purpose of these
notices is to give interested persons an opportunity to participate in
the rule making prior to the adoption of the final rules.
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Federal Register / Vol. 87, No. 142 / Tuesday, July 26, 2022 /
Proposed Rules
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NUCLEAR REGULATORY COMMISSION
10 CFR Part 50
[Docket No. PRM-50-122; NRC-2020-0150]
Accident Source Term Methodologies and Corresponding Release
Fractions
AGENCY: Nuclear Regulatory Commission.
ACTION: Petition for rulemaking; denial.
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SUMMARY: The U.S. Nuclear Regulatory Commission (NRC) is denying a
petition for rulemaking dated May 31, 2020, submitted by Brian
Magnuson. The petitioner requested that the NRC revise its regulations
to codify the source term methodologies and corresponding release
fractions recommended in a report issued by Sandia National
Laboratories; to codify a modified version of draft regulatory guide
DG-1199, including the source term methodologies recommended in the
report and the corresponding release fractions; and to account for high
burnup fuel pellet fragmentation, relocation, and dispersal outside of
the fuel rod during postulated design basis accidents. The NRC docketed
the petition on June 18, 2020, and assigned it Docket No. PRM-50-122.
The NRC is denying the petition because the proposed changes would
unnecessarily reduce the intended flexibility in the NRC's regulatory
approach, and they are not necessary to provide reasonable assurance of
adequate protection of public health and safety.
DATES: The docket for PRM-50-122 is closed on July 26, 2022.
ADDRESSES: Please refer to Docket ID NRC-2020-0150 when contacting the
NRC about the availability of information for this action. You may
obtain publicly available information related to this action by any of
the following methods:
Federal Rulemaking Website: Go to https://www.regulations.gov and search for Docket ID NRC-2020-0150. Address
questions about NRC Docket IDs to Dawn Forder; telephone: 301-415-3407;
email: [email protected]. For technical questions, contact the
individuals listed in the FOR FURTHER INFORMATION CONTACT section of
this document.
NRC Agencywide Documents Access and Management System
(ADAMS): You may obtain publicly available documents online in the
ADAMS Public Documents collection at https://www.nrc.gov/reading-rm/adams.html. To begin the search, select ``Begin Web-based ADAMS
Search.'' For problems with ADAMS, please contact the NRC's Public
Document Room (PDR) reference staff at 1-800-397-4209, 301-415-4737, or
by sending an email to [email protected]. For the convenience of the
reader, instructions about obtaining materials referenced in this
document are provided in the Availability of Documents section.
NRC's PDR: You may examine and purchase copies of public
documents, by appointment, at the NRC's PDR, Room P1 B35, One White
Flint North, 11555 Rockville Pike, Rockville, Maryland 20852. To make
an appointment to visit the PDR, please send an email to
[email protected] or call 1-800-397-4209 or 301-4154737, between 8
a.m. and 4 p.m. (ET), Monday through Friday, except Federal holidays.
FOR FURTHER INFORMATION CONTACT: Adakou Foli, Office of Nuclear Reactor
Regulation; telephone: 301-415-1984; email: [email protected], or
Solomon Sahle, Office of Nuclear Material Safety and Safeguards;
telephone: 301-415-3781; email: [email protected]. Both are staff
of the U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001.
SUPPLEMENTARY INFORMATION:
Table of Contents:
I. The Petition
II. Public Comments on the Petition
III. Reasons for Denial
IV. Availability of Documents
V. Conclusion
I. The Petition
Section 2.802 of title 10 of the Code of Federal Regulations (10
CFR), ``Petition for rulemaking--requirements for filing,'' provides an
opportunity for any interested person to petition the Commission to
issue, amend, or rescind any regulation. On May 31, 2020, the NRC
received a petition for rulemaking (PRM) from Brian Magnuson. The
petitioner requested that the NRC amend its regulations in Sec. 50.67,
``Accident source term,'' to codify the following:
the source term methodologies recommended in the Sandia
National Laboratories report SAND2008-6601, ``Analysis of Main Steam
Isolation Valve Leakage in Design Basis Accidents Using MELCOR 1.8.6
and RADTRAD,'' issued October 2008; and
a modified version of draft regulatory guide (DG) DG-1199,
``Alternative Radiological Source Terms for Evaluating Design Basis
Accidents at Nuclear Power Reactors,'' issued October 2009, that would
include the source term methodologies recommended in SAND2008-6601 and
the corresponding release fractions.
The petition also requested that the NRC revise Sec. 50.67 to
account for high burnup fuel pellet fragmentation, relocation, and
dispersal outside of the fuel rod during postulated design-basis
accidents.
The DG-1199 was a proposed revision to Regulatory Guide (RG) 1.183,
``Alternative Radiological Source Terms for Evaluating Design Basis
Accidents at Nuclear Power Reactors,'' Revision 0, issued July 2000,
and was not finalized as an update to RG 1.183. After the issuance of
DG-1199 for public comment, the staff received a number of public
comments and spent significant efforts in addressing the comments,
including resolving different NRC staff views on the approach in
addressing certain comments. The efforts included soliciting an
independent review of certain aspects of the DG-1199 performed by
Sandia National Laboratories. In 2017, the NRC received the final
responses from Sandia National Laboratories associated with their
independent review.
In late 2020, the NRC resumed RG 1.183 revision efforts after
considering a significant amount of insight gained since the initial
issuance of the DG-1199, including the 2017 Sandia National
Laboratories responses and research pertaining to state-of-the-art
source term knowledge, such as the fuel fragmentation, relocation, and
dispersal. The planned revision will include this information and also
will update RG 1.183 to support accident tolerant fuel
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and higher enrichment and burnup levels.
The petition identified concerns with the NRC guidance used to
calculate radiological doses to comply with the regulations in Sec.
50.67, stating that (1) the current NRC guidance in RG 1.183 is
``conceptually inaccurate'' and ``nonconservative'' based on SAND2008-
6601, and (2) nuclear power plants use varying regulatory guidance
(e.g., Technical Information Document (TID)-14844, ``Calculation of
Distance Factors for Power and Test Reactor Sites,'' issued March 1962;
NUREG-1465, ``Accident Source Terms for Light-Water Nuclear Power
Plants,'' issued February 1995; and RG 1.183) that relies on different
source term methodologies and corresponding release fractions to
satisfy the same regulations. The petition argued that due to these
concerns, many nuclear power plants are ``likely not in compliance with
some, or all of their applicable regulations and requirements, which
ultimately protect people and the environment.'' The petitioner stated
that the proposed revision to Sec. 50.67 would eliminate
inconsistences resulting from the use of different source term
methodologies and release fractions and would provide the requisite
means to ensure compliance with the underlying regulations.
II. Public Comments on the Petition
On August 24, 2020 (85 FR 52058), the NRC published a notice of
docketing of PRM-50-122 and a request for public comment on the PRM in
the Federal Register. The public comment period closed on November 9,
2020. The NRC received two comment submissions: (1) one commenter (the
petitioner) provided supplemental information in support of the
petition, and (2) one commenter (an NRC staff member acting in his
personal capacity) opposed the petition. This latter comment was
withdrawn from the petition docket because it included non-public
information. The NRC reviewed the comments in making its decision on
the petition.
A summary of the comment from the petitioner and the NRC's response
follows. The comment is available as indicated in the Availability of
Documents section of this document.
Comment: The petitioner provided additional concerns related to RG
1.183, Revision 0, such as the treatment of uncertainties in the source
terms and the behavior of main steam isolation valve leakage. He stated
that such issues provide additional justification for codifying a
modified version of DG-1199 in Sec. 50.67.
NRC Response: As discussed in more detail in the Reasons for Denial
section of this document, the NRC disagrees with the comment, and finds
that RG 1.183, Revision 0 continues to provide an acceptable method to
address design-basis accident radiological consequences to comply with
the applicable regulations. With regard to the continued acceptability
of RG 1.183, Revision 0, additional information also appears in the
Differing Professional Opinion case file DPO-2020-002, available as
indicated in the Availability of Documents section of this document.
III. Reasons for Denial
The NRC is denying the petition because the requested changes would
unnecessarily reduce the intended flexibility inherent in Sec. 50.67
and the NRC's overall regulatory approach in the area of design-basis
accident radiological consequence analyses. The NRC's current
regulations and oversight activities continue to provide reasonable
assurance of adequate protection of public health and safety.
Codifying a specific source term methodology and corresponding
release fractions in Sec. 50.67 would unnecessarily limit options for
meeting the requirements, whereas Sec. 50.67 currently allows the use
of alternative sufficient methods of compliance. A detailed approach
for determining source term is provided in RG 1.183, Revision 0, which
describes one way to meet the requirements in Sec. 50.67.
In Sec. 50.67, the NRC provides requirements on the acceptable
dose criteria from the design-basis analyses based upon a major
accident assumed to result in substantial meltdown of the core with
subsequent release of appreciable quantities of fission products (see
Sec. 50.67; see also TID-14844 and NUREG-1465). The regulatory
approach of using design-basis accidents and applying performance-based
regulatory requirements is consistent with the approach provided in
other NRC regulations, including Sec. 50.46, ``Acceptance criteria for
emergency core cooling systems for lightwater nuclear power reactors,''
and Sec. 50.65, ``Requirements for monitoring the effectiveness of
maintenance at nuclear power plants.'' Furthermore, when Sec. 50.67
was promulgated, the NRC did not include a defined methodology for
demonstrating compliance, consistent with other regulations related to
radiological reactor siting criteria, such as Sec. 100.11,
``Determination of exclusion area, low population zone, and population
center distance,'' and Sec. 50.34, ``Contents of applications;
technical information.'' Instead, Sec. 50.67 allows changes to the
defined source term or the development of other technically sound
source term values without requiring additional rulemaking, and the NRC
still finds this approach to be appropriate. Therefore, instead of
codifying a particular source term methodology, the NRC used NUREG-1465
and other technical information to develop RG 1.183 to provide one
acceptable methodology for complying with Sec. 50.67, but not the only
one. This has provided the NRC and the nuclear industry with both
regulatory clarity and the flexibility to consider and incorporate new
research and technical advancements while continuing to ensure safety.
The approach in Sec. 50.67 is to provide flexibility in applying basic
principles to new situations and the use of evolving methods of
analyses in the licensing process, and not to include prescriptive
methodology in the regulation. This approach reflects the philosophy
that the regulation only contains the high-level requirements and that
the technical details are contained in guidance and updated, as
appropriate, to reflect current knowledge. The NRC finds that Sec.
50.67 continues to provide reasonable assurance of adequate protection
and safety given new technologies and continued lessons learned. For
example, the current Sec. 50.67 requires that the application contain
an evaluation of the consequences of applicable design basis accidents.
In addition, Sec. 50.90 requires that applications for license
amendments fully describe the desired changes. Therefore, applicants
and licensees are required to address significant changes to the fuel
design such as increases to fuel burnup limits and potential fuel
fragmentation, relocation, and dispersal issues, and the NRC will only
approve an amendment if the applicant's analysis demonstrates with
reasonable assurance that dose values are met, consistent with the
agency's process.
IV. Availability of Documents
The documents identified in the following table are available to
interested persons through one or more of the following methods, as
indicated.
[[Page 44283]]
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ADAMS Accession
No. or Federal
Document Date Register citation
or web site
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PRM-50-122, ``Petition to Amend 10 CFR 50.67, Accident May 31, 2020..................... ML20170B161
Source Term, to Include Methodologies and Release
Fractions''.
DG-1199, ``Alternative Radiological Source Terms for October 2009..................... ML090960464
Evaluating Design Basis Accidents at Nuclear Power
Reactors''.
SAND2008-6601, ``Analysis of Main Steam Isolation Valve October 2008..................... ML083180196
Leakage in Design Basis Accidents Using MELCOR 1.8.6 and
RADTRAD''.
RG 1.183, ``Alternative Radiological Source Terms for July 2000........................ ML003716792
Evaluating Design Basis Accidents at Nuclear Power
Reactors,'' Revision 0.
NUREG-1465, ``Accident Source Terms for Light-Water February 1995.................... ML041040063
Nuclear Power Plants''.
TID-14844, ``Calculation of Distance Factors for Power and March 23, 1962................... ML021720780
Test Reactors''.
Accident Source Term Methodologies and Corresponding August 24, 2020.................. 85 FR 52058
Release Fractions; Notice of Docketing and Request for
Comment.
Comment (002) of Brian Magnuson on PRM-50-122--Accident November 8, 2020................. ML20330A276
Source Term Methodologies and Corresponding Release
Fractions.
Differing Professional Opinion (DPO) Case File for DPO- March 8, 2021.................... ML21067A645
2020-002.
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V. Conclusion
For the reasons cited in this document, the NRC is denying PRM-50-
122. The current requirements in Sec. 50.67 continue to provide
reasonable assurance of adequate protection of public health and safety
and should not be revised as proposed in the PRM.
Dated: July 19, 2022.
For the Nuclear Regulatory Commission.
Brooke P. Clark,
Secretary of the Commission.
[FR Doc. 2022-15854 Filed 7-25-22; 8:45 am]
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